Author Subjects Method Abstinence Period Results
Cosgrove et al. [88] 19 smokers; 20 non-smokers SPECT, 5-IA 1 day (n=7), 1 week (n=17), 2 weeks (n=7), 4 weeks (n=11), and 6-12 weeks (n=6) Compared to non-smokers, beta(2)*-nAChR availability in smoker striatum, cortex, and cerebellum same after 1 day abstinence, ↑ after 1 week abstinence, same at 4 and 6-12 weeks abstinence
Wüllner et al.
[157]
7 male smokers; 7 male non-smokers PET, 2-FA none ↑total brain distribution volume of 2-FA in smokers, most prominently in cerebellum and brainstem
Mamede et al. [85] 10 male smokers; 6 males non-smokers SPECT, 5-IA 4 hours (n=5), 10 days (n=5), and 21 days (n=5) Binding potential of nAChRs in smokers ↓ 33.5% +/- 10.5% after 4 hours abstinence, ↑ 25.7% +/- 9.2% after 10 days abstinence, and ↓ to nonsmoker level after 21 days abstinence
Staley et al. [86] 16 smokers; 16 non-smokers SPECT, 5-IA 7 days Compared to non-smokers, recently abstinent smokers had ↑ 5-IA uptake in striatum, parietal cortex, frontal cortex, anterior cingulate, temporal cortex, occipital cortex and cerebellum
SPECT = single-photon emission computed tomography; 5-IA = (S)-5-[(123)I]iodo-3-(2-azetidinylmethoxy)pyridine; nAChR = nicotinic acetylcholine receptor; PET = position emission tomography; 2-FA = 2-[(18)F]fluoro-3-(2(S)azetidinylmethoxy)pyridine
Table 2: Up-regulation of alpha4beta2* nicotinic acetylcholine receptors in chronic smokers and following acute, but not prolonged, abstinence.